Sun-like star hosts Kepler’s first confirmed habitable zone planet

NSA's Kepler probe keeps spotting planet candidates, and has its first …

This week, NASA is playing host to a conference dedicated to the results pouring in from Kepler, its first dedicated planet-hunting probe. The space-based telescope spots planets as they pass in front of their host star and temporarily reduce the amount of light from the star that reaches Kepler's sensors; ground based observatories are then used to confirm these planetary candidates. Right now, that confirmation process is turning out to be the big hold-up, as Kepler has identified over 2,300 planet candidates, of which only 28 have been confirmed. But NASA has announced that one of the confirmed planets sits in the habitable zone of a sun-like star.

The initial period of planet spotting was heavily biased towards heavy, Jupiter-sized planets, which were the easiest things to spot. Kepler has completely changed that; the vast majority of the planet candidates are either Super-Earths or Neptune-sized, and just over 200 candidates are roughly the size of our own planet. Forty-eight of these candidates lie in the habitable zone of their stars, where liquid water on the surface is a possibility; 10 of those are roughly Earth-sized. That's actually a small drop from previous counts, as NASA has added consideration of atmospheric warming driven by greenhouse gasses when calculating whether liquid water is likely to be present.

Attention was then focused on the Kepler-22 system, where there was a planet candidate, Kepler-22b, that orbits on the inner edge of the habitable zone. If it were in our solar system, Kepler-22b would orbit somewhere between Venus and the Earth; its orbits take 290 days.

Follow-up observations with the Spitzer space telescope have now confirmed the presence of Kepler-22b, making it the first confirmation of a habitable zone planet by the program. Right now, all we can say about the planet is that it has a radius that's about 2.4 times that of Earth's. Since we don't know its mass, we can't calculate its density, and thus its most likely composition. And, since it's 600 light years away, it will be hard to get a much better look any time soon.

The vast backlog of planet candidates indicates that we'll probably be sorting through Kepler data for years. But the other habitable zone candidates are likely to be high priorities for follow-up observations, so there's a good chance we'll be hearing more about those sooner rather than later.

I think the current best method is to watch for the "wobble" introduced to the star's motion as the planet orbits. Unfortunately, the wobble is proportional to the planet's mass and frequency of orbit, both of which are pretty small in this case.

I think the current best method is to watch for the "wobble" introduced to the star's motion as the planet orbits. Unfortunately, the wobble is proportional to the planet's mass and frequency of orbit, both of which are pretty small in this case.

Only radio waves or artificial light could confirm that the planet is inhabitable, but if they reached that level of civilization, they were probably close to green house gas Armageddon, so 600 years later it would be uninhabitable...certainly by the time we got there.

Anyone want to help me get a head-start on hollowing out Deimos? We can call call our club something catchy like "Unified Earth Space Council", and I'll bring pizza for everyone!

I'm thinking we could name our ship after something that takes a lot of effort and time; maybe the UESC Souffle?

We'll need some Lisp or Prolog (or similar) hackers to help code up adaptive management systems, of course. QA testing is for the weak, though, so if you just want to write unit tests you can stay home.

Anyone want to help me get a head-start on hollowing out Deimos? We can call call our club something catchy like "Unified Earth Space Council", and I'll bring pizza for everyone!

I'm thinking we could name our ship after something that takes a lot of effort and time; maybe the UESC Souffle?

We'll need some Lisp or Prolog (or similar) hackers to help code up adaptive management systems, of course. QA testing is for the weak, though, so if you just want to write unit tests you can stay home.

Sounds good, we'll need to do something about security though. But beyond that it's a great concept, I'm all pfhor it!

And, since it's 600 light years away, it will be hard to get a much better look any time soon.

Yes, if you want to provide stimulation for funding *now,* then a "candidate" planet that might or might not bear life a mere 600 light years from earth seems like a great place to start...! What's the downside? There isn't any, because we'll all be long dead when any data to the contrary, or to the pro, will actually become verifiable... The idea here isn't hard science since there's mighty slim scientific pickin's of that sort to be had here--the idea is to ignite the imagination of John Q Public--and I really do heartily approve of that.

Is there anyway to confirm more fully the size or mass of the planet? Couldn't the wobbles be "lying" to us? More than one system might produce the same wobbles right??

Also... Anyway to get some idea of the elements ont he surface/atmosphere of the planet? Does any kind of spectrography have a chance in hell at this range? How about focusing on the system for a very long time like the deep field photos? Then see if you get any kind of vague 1 pixel image of the planet that might tell you what elements are there?

Only radio waves or artificial light could confirm that the planet is inhabitable, but if they reached that level of civilization, they were probably close to green house gas Armageddon, so 600 years later it would be uninhabitable...certainly by the time we got there.

where were we at 600 years ago? might not have been able to tell what was going on here either from that distance...

If we were to find one of these 'habitable' planets closer, say within 20 light years, do we have the technology right now, to build a probe that could accelerate to say a tenth of the speed of light and be able to get there in 200 years and beam some data about the system to us? The biggest hurdles I can think of are a power source that could last that long, a powerful enough transmitter and a sensitive enough receiver.

financially it'd be quite impossible i'm sure. No government would ever justify a science project where the data would be interpreted by our descendants 9 or 10 generations ahead of us, but it's an interesting thought experiment none the less.

If we were to find one of these 'habitable' planets closer, say within 20 light years, do we have the technology right now, to build a probe that could accelerate to say a tenth of the speed of light and be able to get there in 200 years and beam some data about the system to us? The biggest hurdles I can think of are a power source that could last that long, a powerful enough transmitter and a sensitive enough receiver.

financially it'd be quite impossible i'm sure. No government would ever justify a science project where the data would be interpreted by our descendants 9 or 10 generations ahead of us, but it's an interesting thought experiment none the less.

It would be in the trillions of dollars range, and would have to use nuclear pulse propulsion, which means there would be potential for environmental catastrophe during the launches (it would have to be assembled in space), but we could do it in principle if not in practice.

The more I think about it, I am not sure how impossible that funding goal would really be with the right evidence. We could detect oxygen spectroscopically in the atmosphere in large concentrations, say, which is 100% proof of ongoing photosynthesis. With that kind of "there is definitely, without doubt, life at least passingly similar to that on Earth on this planet" evidence, I can just barely imagine world governments being willing to cough up a collective $10 trillion.

Also, it's completely plausible that Alpha Centauri, only 4 light years away, has a habitable planet or moon. 20 light years is right at the furthest extent of feasibility, but there are better case scenarios where our destination is "right next door."

It would be in the trillions of dollars range, and would have to use nuclear pulse propulsion, which means there would be potential for environmental catastrophe during the launches (it would have to be assembled in space), but we could do it in principle if not in practice.

And it is fallacy to think we build something that survive the trip. The simple fact is that researching outer space is a complete until someone figures out FTL (which currently seems impoossible). We should be focusing on things that make sense. Solar power, wind power, fusion is worth a try. Planets 1 light year away are pretty much irrelevant. I have no major problem scanning the skies since that is cheap. But I would not waste money on anything more.

You are no doubt concerned about collisions with micrometeoroids being like nuclear explosions at .1c. True. Our spacecraft is *powered* by fusion bombs. It can take a hit. It's expensive as hell to build that kind of robustness in, but designers much more expert than me have said it's feasible.

If we were to find one of these 'habitable' planets closer, say within 20 light years, do we have the technology right now, to build a probe that could accelerate to say a tenth of the speed of light and be able to get there in 200 years and beam some data about the system to us? The biggest hurdles I can think of are a power source that could last that long, a powerful enough transmitter and a sensitive enough receiver.

Just broadcast over and over to that planet and hope something interesting gets back in 40 years...

You are no doubt concerned about collisions with micrometeoroids being like nuclear explosions at .1c. True. Our spacecraft is *powered* by fusion bombs. It can take a hit. It's expensive as hell to build that kind of robustness in, but designers much more expert than me have said it's feasible.

Taking a hit to a damped pusher plate is a bit different than taking a hit to the face, innit? What if said micrometeoroid came from the front?

Does it stay feasible if we make the whole thing as tough as a pusher plate? And Will that preclude fine maneauvering and deploying probes when it gets to the system itself?

If we were to find one of these 'habitable' planets closer, say within 20 light years, do we have the technology right now, to build a probe that could accelerate to say a tenth of the speed of light and be able to get there in 200 years and beam some data about the system to us? The biggest hurdles I can think of are a power source that could last that long, a powerful enough transmitter and a sensitive enough receiver.

financially it'd be quite impossible i'm sure. No government would ever justify a science project where the data would be interpreted by our descendants 9 or 10 generations ahead of us, but it's an interesting thought experiment none the less.

If you throw enough money at that problem, you could do it probably. Would be too much money of course.

But there are lots of things you could do for much cheaper. Space-based telescopes to at least check the atmosphere of that planet are just a bit expensive, but in no way prohibitively expensive. Finding water and oxygen in the atmosphere of such a planet would then surely allow more money to be thrown at learning more.

All in all I would say you get much more bang for the buck this way. To a certain extent of course, but building even really large (clusters of) space-based telescopes is still much cheaper (and much faster) than actually going there.

Sadly, about all (very realistic and not at all that expensive) projects of this kind have been cancelled meanwhile. Personally I would think such projects are much more interesting than sending the n-th probe to Mars, but this seems to be just too far out, literally.

You are no doubt concerned about collisions with micrometeoroids being like nuclear explosions at .1c. True. Our spacecraft is *powered* by fusion bombs. It can take a hit. It's expensive as hell to build that kind of robustness in, but designers much more expert than me have said it's feasible.

Taking a hit to a damped pusher plate is a bit different than taking a hit to the face, innit? What if said micrometeoroid came from the front?

Does it stay feasible if we make the whole thing as tough as a pusher plate? And Will that preclude fine maneauvering and deploying probes when it gets to the system itself?

Put a small shield on the front made of the same stuff on the back. It adds maybe a few tons to your spacecraft, but who cares? The thing weighs hundreds of tons already, most of that He-3/H-2 fuel.

I've looked up more details. The spacecraft already has 2 shields because it needs to slow down at some point, so you get protection from frontal collision "for free."

You are no doubt concerned about collisions with micrometeoroids being like nuclear explosions at .1c. True. Our spacecraft is *powered* by fusion bombs. It can take a hit. It's expensive as hell to build that kind of robustness in, but designers much more expert than me have said it's feasible.

Taking a hit to a damped pusher plate is a bit different than taking a hit to the face, innit? What if said micrometeoroid came from the front?

Does it stay feasible if we make the whole thing as tough as a pusher plate? And Will that preclude fine maneauvering and deploying probes when it gets to the system itself?

Put a small shield on the front made of the same stuff on the back. It adds maybe a few tons to your spacecraft, but who cares? The thing weighs hundreds of tons already, most of that He-3/H-2 fuel.

I've looked up more details. The spacecraft already has 2 shields because it needs to slow down at some point, so you get protection from frontal collision "for free."

Thanks! Yes a wide front shield solves it nicely. I was thinking more of a hugely tough soccer ball or cube of pusher plates. That would be awkward ofcourse.

But...they using nukes for slowing down too? lol. WOW. That makes me hysterical for some reason...even though it makes perfect sense.

Put a small shield on the front made of the same stuff on the back. It adds maybe a few tons to your spacecraft, but who cares? The thing weighs hundreds of tons already, most of that He-3/H-2 fuel.

I've looked up more details. The spacecraft already has 2 shields because it needs to slow down at some point, so you get protection from frontal collision "for free."

I don't know why you would build two proposion systems when you could turn the ship around to slow down but I think a front shield would be of marginal benefit. I wonder how a hit on the edge of the shield is managed (I can just see a wildly spinning ball of space junk). And that is just for micrometeoroids - if you get unlucky you might meet something a little larger. Plus you somehow have to design a control system that will last more than 100 years - nothing we have built yet comes even close. Nuclear pulse proposion should be reserved for attempting to take out approaching astroids.

I don't know why you would build two proposion systems when you could turn the ship around to slow down...

I misinterpreted the article before, reading quickly. They have only one engine, but have shields on both sides because they must turn around. The statement was only that they must have two shields because eventually the probe must slow down. Reading further, it is the orientation that causes the need for two shields, so it is *not* free. My mistake. It's still a small mass next to the spacecraft's total size.

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I wonder how a hit on the edge of the shield is managed (I can just see a wildly spinning ball of space junk). And that is just for micrometeoroids - if you get unlucky you might meet something a little larger.

The momentum of a hundreds-of-ton spacecraft at .1c cares not for a pebble. The energy release is huge, the momentum transfer is huge, but only because the momentum of our spacecraft is so much larger. The odds of meeting something larger in interstellar space are ridiculously small. The asteroid belt has a much higher concentration of large-ish objects, and no interplanetary probe will ever hit one.

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Plus you somehow have to design a control system that will last more than 100 years - nothing we have built yet comes even close.

The Voyager probes, built in the 1970s, are still going more than 30 years later and will still be going into the 2020s. That's not 100 years, but it's a significant enough fraction that I (and NASA) have great confidence in the feasibility of a 100 year machine. I obviously can't offer proof of a comparable machine lasting for 100 years because the manufacturing skills of 1911 aren't exactly representative of today.

As far as using nukes for propulsion - The major force from a nuclear explosion comes from the shock wave it creates in air. In a vacuum, it'd likely be no more than a higher than normal solar wind. Then it'd be over in an instant. High impulse, low thrust. Plus you'd now have to deal with space debris, which can obstruct your view of the stars and all that fun stuff, thus completely destroying any form of navigation (and that's not considering the damage it could potentially do to the ship). In other words, it sounds cool but funding would probably be better spent in more rational forms of propulsion.

That aside, if the star this planet orbits is also a third generation star, then due to the position of it's orbit it's possible it could have the same general make up as our planet. With this "possibility" then we could have some fun with numbers by assuming its properties are consistent with that of our planet.

A 2.4x diameter means (using the equation for the volume of a sphere), that the volume of that planet is 13.8 times that of our own. With the same density in both planets, that means that the people who live on that planet would most likely be quite short and strong, living in a 13.8g environment.

This is just spit-balling numbers. It's possible this is the case, but it's also possible that I can go to the nearest gas station and buy a winning lotto ticket.